Jetty-Less Offshore Terminal Configurations

ABSTRACT

Systems and methods provide for offloading liquefied gas, e.g. LNG, from a cargo vessel offshore and regasifying the offloaded gas. In example systems, a floating storage unit is moored to the seabed offshore; first tubing offloads liquefied gas from the cargo vessel to the storage unit; a jack-up platform is positioned offshore in proximity to the floating storage unit, the jack-up platform comprising legs which are arranged to be supported on the seabed and a hull which is arranged to be jacked up along the legs to a position above the sea surface; a regasification facility is provided on the jack-up platform; second tubing extends between the storage unit and the regasification facility of the jack-up platform for transferring liquified gas from the cargo vessel to the regasification facility for regasification of the liquified gas; and third tubing communicates regasified gas away from the regasification facility, e.g. to shore.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of U.S. ProvisionalApplication Ser. No. 62/591,821, filed Nov. 29, 2017, which applicationis hereby incorporated by reference in its entirety.

The present invention relates to offshore terminals for vessels, and inparticular, jetty-less systems and methods for the offloading or loadingof fluid cargo off or onto a vessel at an offshore terminal. In someexamples, the cargo is liquefied natural gas (LNG), and a regasificationunit can be utilized for regasifying the LNG into gas.

BACKGROUND

Terminals of various kinds have been devised for loading fluid cargoonto a vessel or offloading fluid cargo from a vessel. Infrastructureand cost for onshore terminals can be considerable, and approvalprocesses can be demanding.

In the LNG industry, a traditional solution for an LNG receivingterminal is to construct a near-shore jetty where a floating storageunit (FSU), or a floating storage and regasification unit (FSRU) ismoored to the jetty. Such jetties may be very capital intensive, and cantake a long time to construct. It may also be challenging to obtain anenvironmental permit for construction of the near-shore jetty as thefootprint is typically large (typical length of 300-400 m+potentialbreakwater structure). To address this, solutions have been proposed foroffloading LNG from the cargo vessel offshore. However, mooring anFSU/FSRU to an exposed offshore jetty during high wind and waves may bechallenging and provide significant limitations for such a terminalset-up.

Published US Patent Application US 2017/0253302 describes an LNGterminal where LNG may be transferred offshore from a visiting LNGcarrier to a spread-moored Floating Storage Unit (FSU) or FloatingStorage and Regasification Unit (FSRU). The solution is “jetty-less”. Nojetty is required for mooring the vessels or other facilities.

There is currently a large demand for offshore LNG receiving terminalswhere the LNG is regasified and sent to an onshore power plant or to anonshore gas pipeline. If regasification is required for transport toland, this can be achieved through the regasification facility onboardthe FSRU. However, FSRU's are typically relative expensive and can havelimitations.

Alternatives of transporting large volumes of LNG to shore in liquidform in insulated pipelines may be prohibitively expensive and/orrequire high performance characteristics.

SUMMARY

According to a first aspect of the invention, there is provided a systemfor offloading liquefied gas from a cargo vessel and regasifying theoffloaded gas at a location offshore, the system comprising: a floatingstorage unit which is moored to the seabed offshore; first tubing foroffloading liquefied gas from the cargo vessel to the storage unit; ajack-up platform positioned offshore in proximity to the floatingstorage unit, the jack-up platform comprising legs which are arranged tobe supported on the seabed and a hull which is arranged to be jacked upalong the legs to a position above the sea surface; a regasificationfacility on the jack-up platform; second tubing extending between thestorage unit and the regasification facility of the jack-up platform fortransferring liquified gas from the cargo vessel to the regasificationfacility for regasification of the liquified gas; and third tubing forcommunicating regasified gas away from the regasification facility.

The floating storage unit may be spread-moored to the seabed. Thefloating storage unit may comprise a floating storage vessel, e.g. aship, or other vessel.

The system may further include the cargo vessel. The cargo vessel may bespread-moored to the seabed. Alternatively, the cargo vessel may bemoored side-by-side to the floating storage unit.

The cargo vessel may be spread moored at sea to a plurality of mooringpoints for mooring the cargo vessel in a desired orientation, theliquefied gas to be offloaded from the cargo vessel. The first tubingmay be configured to be connected to the cargo vessel for fluidcommunication between the cargo vessel and the floating storage unit.The first tubing may comprise a first portion configured to be connectedto the cargo vessel and a second portion configured to be connected tothe floating storage unit. The system may further comprise a travel unitoperable to travel across the sea and carry part of the first tubing,e.g. from a stand-by location, to a position at or adjacent to the cargovessel, e.g. so as to allow an end of the first portion of the firsttubing to be connected to the cargo vessel for offloading the liquefiedgas through the tubing, whereby the liquefied gas may be transmitted tothe travel unit through the first portion of tubing and away from thetravel unit to the floating storage unit through the second portion offirst tubing. The unit may have at least one lifting and handlingdevice, e.g. crane or articulated arm extender, which with the firstportion of the first tubing coupled thereto and when the travel unit ispositioned at or adjacent to the cargo vessel may be operable to lift,maneuver, and land the end of the first portion of the first tubing onthe cargo vessel for arranging the end of the first portion of the firsttubing at or near a manifold on the cargo vessel for connection thereto.The system may further comprise a chain crawling propulsion systemwherein at least one chain may be anchored to the seabed, and the travelunit may be configured to draw in the chain while the chain is anchoredin order to propel the unit for travel across the sea into the positionadjacent to the cargo vessel.

The system may further comprise a power plant on the jack-up platformprovided with a regasification facility or the regasification facilityis provided or on another jack-up platform. The power plant may beconfigured to be supplied with regasified gas from the regasificationfacility.

The system may further comprise a fresh water generation facility whichmay be configured to be powered using electrical power generated by thepower plant. The fresh water generation facility may be disposed on oneof: the jack-up platform with the regasification facility; the jack-upplatform with the power plant; or another jack-up platform.

The liquified gas may typically comprise liquefied natural gas, LNG, orliquefied petroleum gas, LPG.

According to a second aspect of the invention, there is provided asystem for offloading liquefied gas from a cargo vessel at a locationoffshore, the system comprising: a floating storage unit which is mooredto the seabed; first tubing for offloading liquified gas from the cargovessel to the storage unit; a regasification facility; an intermediatestructure positioned offshore in proximity to the storage unit, theintermediate structure arranged to be supported on the seabed; aconnection manifold or device above the sea surface on the intermediatestructure; second tubing configured to extend between the storage unitand the connection manifold or device on the intermediate structure fortransferring liquified gas from the cargo vessel to the intermediatestructure; third tubing arranged on the seabed for conveying liquefiedgas from the intermediate structure to the regasification facility.

According to a third aspect of the invention, there is provided systemfor offloading liquefied gas from a cargo vessel and regasifying theoffloaded gas at a location offshore, the system comprising: a floatingstorage unit which is moored to the seabed offshore, the floatingstorage unit comprising an upright cylindrical hull; tubing foroffloading fluid from the cargo vessel to the storage unit; and aregasification facility on the floating storage unit.

According to fourth aspect of the invention, there is provided a systemfor offloading liquefied gas from a cargo vessel at a location offshoreand regasifying the offloaded gas, the system comprising: a floatingstorage unit which is moored to the seabed offshore; tubing foroffloading fluid from the cargo vessel to the storage unit; at least onejack-up platform; and a regasification facility; wherein any one or moreof the regasification facility a power production facility and a watergeneration facility is disposed on the jack-up platform; the powerproduction facility being operable using regasified gas from theregasification facility.

According to a fifth aspect of the invention, there is provided a systemfor offloading liquefied gas from at least one cargo vessel andregasifying the offloaded gas at a location offshore, the systemcomprising: a jack-up platform; tubing for offloading liquified gas fromthe cargo vessel to the jack-up platform; and a regasification facilityon the jack-up platform for regasifying the offloaded gas.

According to a sixth aspect of the invention, there is provided a methodof offloading liquified gas from a cargo vessel and regasifying theoffloaded gas using the system in accordance with any of the first tofifth aspects of the invention.

According to seventh aspect of the invention, there is provided a systemfor liquefying gas and loading the liquefied gas onto a cargo vessel andat a location offshore, the system comprising: a floating storage unitwhich is moored to the seabed; a jack-up platform positioned offshore inproximity to the floating storage unit, the jack-up platform comprisinglegs which are arranged to be supported on the seabed and a hull whichis arranged to be jacked up along the legs to a position above the seasurface; a liquefaction facility on the jack-up platform; tubing forloading liquefied gas fluid from the floating storage unit to the cargovessel; tubing extending between the floating storage unit and theliquification facility of the jack-up platform for transferringliquified gas from the liquification facility to the cargo vessel; andthird tubing for transporting the gas to the liquefaction facility.

According to an eighth aspect of the invention, there is provided amethod of liquefying gas and loading liquified gas onto a cargo vesselusing the system in accordance with the seventh aspect of the invention.

Any of the aspects of the invention may include further features asdescribed in relation to any other aspect, anywhere herein. The systemin any of the aspects is preferably and advantageously a jetty-lesssystem. Various advantages and improvements will be apparent fromthroughout the present specification.

BRIEF DESCRIPTION OF DRAWINGS

These and other aspects of the invention will now be described, by wayof example only, with reference to the accompanying drawings, in which:

FIG. 1 is an overhead representation of a system for offloadingliquefied gas from a cargo vessel and regasifying the offloaded gas at alocation offshore;

FIG. 2 is a side-view representation of part of the system of FIG. 1showing the floating storage unit end-on;

FIG. 3 is a side-view representation of a regasification unit on ajack-up rig for the system of FIGS. 1 and 2;

FIG. 4 is an overhead representation of the jack-up rig of FIG. 3;

FIGS. 5A to 5C are side-view representations of the jack-up rig of FIGS.3 and 4 in successive stages of installation;

FIG. 6 is an overhead representation of a system for liquefying gas andloading the liquefied gas onto a cargo vessel;

FIG. 7 is an overview representation of the system of FIG. 1 expanded toinclude a power plant;

FIG. 8 is a side view of the power plant of the system of FIG. 7 wheninstalled on seabed;

FIG. 9 is a top view of the power plant of FIG. 8;

FIG. 10 is another side view of the power plant of FIGS. 7 and 8 inlarger scale;

FIG. 11 is an overhead representation of a system of FIGS. 1 and 7expanded to include a water generation facility;

FIG. 12 is an overhead representation of a system for offloadingliquefied gas and regasifying the offloaded gas at a location offshore;

FIG. 13 is a side view of the system of FIG. 12;

FIG. 14 is a side view representation of the system of FIGS. 12 and 13with the cargo vessel absent;

FIG. 15 is an overhead representation of the system in the configurationof FIG. 14;

FIG. 16 is an overhead representation of is an overhead representationof a system for offloading liquefied gas and regasifying the offloadedgas at a location offshore;

FIG. 17 is a side-view representation of the system of FIG. 16;

FIG. 18 is a side-view representation of part of the system of FIGS. 16and 17 in larger scale;

FIG. 19 is an overhead view of a system for offloading liquefied gas andstoring the offloaded gas in a circular platform;

FIG. 20 is a close-up view of the platform of the system of FIG. 19; and

FIG. 21 is an overhead view of another system for offloading andregasifying gas from a vessel.

DETAILED DESCRIPTION

Referring to FIGS. 1 to 4 and FIGS. 5A to 5C, a system 1 is generallydepicted for offloading liquefied natural gas (LNG) from a cargo vesselin the form of an LNG carrier 10 and regasifying the offloaded gas at alocation offshore. The system 1 includes a floating storage unit (FSU)in the form of a storage vessel 20. The storage vessel 20 isspread-moored to the seabed by seabed moorings 24.

A jack-up platform 30 is positioned offshore in proximity to the storagevessel 20, and a regasification facility is provided on the jack-up rigfor regasifying the LNG which is offloaded from the LNG carrier 10.

The jack-up platform 30 has legs 31 which are arranged to be supportedon the seabed and a hull 32 which is arranged to be jacked up along thelegs 31 to a position above the sea surface 3. The installation of thejack-up 30 takes place through manoeuvring the hull 32 into theindicated position with the legs 31 in raised position (FIG. 5A),lowering the legs 31 to engage the seabed 2 (FIG. 5B), and then movingthe hull 32 upward along the legs to the position where the bottom ofthe hull is spaced well above the wave zone of the sea surface 3 (FIG.5C).

First tubing 70 extends between the carrier 10 and the storage vessel 20and provides fluid communication for offloading the LNG from the LNGcarrier 10 to the storage vessel 20 through the first tubing.

Second tubing 80 extends between the storage vessel 20 and theregasification facility 35 of the jack-up rig 30 for transferring LNGfrom the storage vessel 20 to the regasification facility forregasification. The second tubing 80 is in the form of hoses which areaerial hoses (not in the water) which are suspended in U-shape in theair between the storage vessel 20 and the jack-up 30.

Third tubing 90 is provided for transporting the regasified gas from theregasification facility 35 to shore, e.g. through a seabed pipeline.

The LNG carrier 10 is moored to the seabed through seabed buoy moorings14 (e.g. a Conventional Buoy Mooring system—CBM), a distance away fromthe storage vessel 20. The LNG carrier 10 visits from time to time tooffload LNG to the storage vessel 10. After offloading to the storagevessel 20, the LNG carrier 10 departs, e.g. to collect a new amount ofLNG from a supplier.

Typically, the storage vessel 20 has greater storage capacity for LNGthan the LNG carrier 10. The storage vessel 20 remains in place on apermanent basis, and together with the jack-up platform 30 provides anoffshore terminal which provides regasification.

The system 1 includes in this example a floating travel unit 60. Thefloating travel unit 60 is configured to travel between the storage unit20 and the LNG carrier 10 to facilitate connection of the first tubing70 to the mid-ships cargo manifold 11 of the LNG carrier 10. When theLNG carrier 10 has been moored, the floating travel unit 60 travels froman initial position, typically near the storage vessel 20, across thesea on a path toward and into position adjacent to a side of the LNGcarrier 10. A length of the tubing 70 to be connected to LNG carrier 10is carried by the travel unit to the LNG carrier 10. The travel unit 60has a lifting and handling device, e.g. a crane, which comprises a boomwhich is used to reach over the side of the LNG carrier and lift andmanoeuvre a tubular end section 70 e of the first tubing 70, over theside of the LNG carrier and land the end section 70 e onto a surface infront of the cargo manifold of the cargo vessel for connection thereto.

The travel unit 60 operates to move into the position adjacent to theLNG carrier 10 by a chain crawling propulsion system. Seabed anchoredchains 64 are provided and the travel unit 60 has winches or deviceswhich are selectively operable to draw in the relevant anchored chain 64so as to propel the unit 60 across sea and into the position adjacent tothe LNG carrier 10 as depicted. The travel unit 60 can be the connectionunit 30 as described in published US patent application US 2017/0253302,and the chain crawling propulsion system may be that as described inpublished US patent application US 2017/0253302 for the connection unitdescribed therein, and the disclosures of these are incorporated hereinby reference.

The fluid cargo may in other variants be liquefied petroleum gas (LPG).

As can be appreciated, the system 1 does not require use of a jetty orany mooring to the jetty of any of: the storage vessel 20; theregasification facility 35 and/or platform 30; and the LNG carrier 10.Nor are any of these moored to each other in the system 1. The mooringsare to the seabed only. The system 1 can advantageously allow transferof fluid cargo offshore, far away from shore, at sea. Large separationdistance is also achieved between the cargo vessel and the storagevessel (typ. 150 m or more) providing safe fluid transfer between thevessels.

The installation and removal of the jack-up platform 30 can for examplebe performed as in the following. When arrived at location, the platform30 uses an onboard jacking system to lower the platform legs 31 onto theseabed 2. The jacking system operates to lift the hull 32 of theplatform off the water to suitable elevation, e.g. 15-20 m above thewaterline. The platform legs are locked at this position and the jackingsystem is removed from the platform and returned to shore. The jackingsystem can thus be standardized and leased to each project to save costas well as maintenance. Removal of the jack-up platform can be performedin the reverse order to the installation, e.g. when a project isfinished and/or to relocate the jack-up platform. To do so, the jackingsystem is brought out to the platform 30 and the hull 32 is jacked downuntil it floats. The legs 31 are pulled up and the platform 30 cansimply be towed to the new location by a standard tug boat or use of asubmersible barge.

Referring to FIG. 6, instead of the regasification facility 35 on thejack-up platform 30, a gas liquefaction facility 135 is provided onjack-up 130. The system 101 in FIG. 6 is therefore arranged forliquefying gas supplied to the liquefaction facility 135 through thirdtubing 90. The liquefied gas, e.g. LNG, is transferred through secondtubing 80 onto the long-term storage facility 20, then transferredthrough first tubing 70 and loaded onto a visiting cargo vessel 10through the cargo manifold 11. Alternatively, the gas for liquefactionis delivered to the facility 135 by other means.

In FIGS. 7 to 10, the system 1 is expanded to include a power plant 235on a separate jack-up platform 230 which includes a hull 232 and legs231. The jack-up platform 230 can be installed in the same manner as thejack-up platform 30. Some of the regasified gas from the regasificationfacility 35 is supplied to the power plant 235 to produce electricalpower. The electrical power is supplied to shore or other receiverthrough power cable 297. Some of the regasified gas is also supplied toshore through third tubing 90, e.g. through subsea pipeline. Theregassification facility may also be located on the same jack-upplatform as the power plant.

In FIG. 11, the system 1 is expanded further to include a watergeneration facility 335 on a separate jack-up platform 330. Power fromthe power plant 235 is used to operate the facility 235 which convertsseawater to freshwater. The freshwater may be supplied to shore throughwater pipe 397. The water generation facility may also be located on thesame jack-up platform as the power plant.

Referring now to FIGS. 12 to 14, the LNG carrier 10 is instead mooredside-by-side to the storage vessel 20. The system 401 of FIGS. 12 to 14,therefore does not have the travel unit 60 of the above described system1. The first tubing is in the form of hosing 470 for offloading LNG fromthe LNG carrier 10 to the storage vessel 20. The storage vessel 20 ismoored to the seabed 2, and the LNG carrier 10 is moored to the storagevessel 20. LNG is transferred from the storage vessel 20 through hosing80 and regasified on the regas facility 35 of the jack-up platform 30.When offloaded, the LNG carrier 10 departs, leaving the storage vessel20 and the regas platform 30 in place (see FIGS. 14 and 15), where itmay continue to process and regasify the LNG from the tanks of thestorage vessel 20 and supply the regasified gas to shore through thirdtubing 90.

In such a case, to allow the LNG carrier to be positioned alongside thestorage vessel 20, the mooring lines 426 from the storage vessel 20 areconnected slightly below the keel of the FSU 20. Additional water depthmay typically then be required to accommodate this mooringconfiguration. Hence, the solution may be best suitable for areas wheresufficient water depth while preferably close enough to shore to avoidinstallation of a long high-pressure gas pipeline.

The described side-by side mooring configuration may also be used incombination with a power plant, water generation facility or gasliquefaction facility described previously.

Turning now to FIGS. 16 to 18, a seabed tower 530 is used in place ofthe jack-up platform 30 with the regasification plant. The seabed towerhas a manifold 534 into which end portion 80 e of the second tubing 80is connected. The manifold 534 is positioned on a platform 532 above thesea surface. The platform 532 is supported on the seabed 2 on at leastone leg 530 which extends upward from the seabed penetrating through thesea surface 3. A conduit connects the manifold fluidly with a seabedpipeline 90. The system 501 is therefore provided such that the LNG isoffloaded and transferred to the storage vessel (FSU) 20 in the same wayas in the system 1. However, the LNG in this example is transported fromthe storage vessel 20, into the manifold 534 on the tower 530, throughthe conduit 536 and into the pipeline 90 through which it travels inliquefied form at high pressure to shore or to a downstream facility forregasification. An insulated LNG Pipe In Pipe (PIP) 90 is then typicallyused from the FSU to the onshore facilities. To limit cost and potentialtemperature effects, the storage vessel 20 (FSU) may typically belocated in very shallow water for obtaining a preferably shortestpossible LNG pipeline to shore.

Alternatively, the storage vessel 20 can include a regasificationfacility, i.e. forms an FSRU, such that regasified LNG is conveyed fromthe storage unit 20 to the tower 530 and into the pipeline 90 to shore.The tower platform 530 e.g. a “tripod tower” can make it feasible tomoor a FSRU in shallower water and yet still enable a safe and robusttransfer of high-pressure gas from the FSRU to the onshore gas pipeline90.

The seabed tower 530 may also be used in combination with theside-by-side mooring configuration described previously instead of thetravel unit 60 shown in FIG. 16.

Referring to FIGS. 19 and 20, a regasification unit 630 is provided inthe form of a platform having a circular section moored to the seabed.LNG is offloaded from the LNG carrier 10 through tubing 70 to the unit620 and regasified gas is transferred through tubing 90 to shore.Optionally, the regasification unit 630 includes a power productionfacility and/or fresh water production facility, or alternatively eitherof these can be provided on separate platforms. The unit providesstorage for offloaded LNG and a regasification facility 635 forregasifying the LNG from tanks on the unit. This can be suitable forsmall scale LNG operations where the amount or frequency of LNG receivedis limited so as to be within the storage capacities and processingrates. A travel unit 60 may be used to connect the tubing 70 to the unit630. The unit 630 is circular in section which provides highlyfavourable motion characteristics when exposed to waves.

The unit 630 may have Bi-lobe-Shaped IMO Type C LNG tanks 613 forstoring the offloaded LNG. These tanks 613 are arranged as 60 degree“cake slices” around the circumference of the unit 630 and may be anattractive solution for efficient and maximizing storage. In otherimplementations however, other LNG containment systems or tanks mayalternatively be used.

In FIG. 21, a jack-up platform 730 is provided with a regasificationfacility 735. The system 701 does not require use of the travel unit 60or floating storage vessel 20. In use, a first articulated tug and barge710 arrives and is moored to the Seabed Buoy Mooring System. A floatingLNG hose is reeled out form the platform 730 and connected to aspecially designed hose connector at the barge 710. LNG is pumped fromthe first barge 710 to the platform 730 and the regasification operationstarts using the regasification facility 735. The tug 723 used for thefirst barge 710 then leaves to pick up a second articulated tug andbarge 723. The second barge 723 arrives and is moored to seabedmoorings. The process of pumping the LNG from second barge 723 startsand progresses slowly when the first barge 710 is nearly empty. Thepumping rate from the second barge 723 is reduced until the first barge710 is empty. In this way, continuous LNG supply to the regasificationplatform 730 can be obtained without installing an FSU or onshore LNGstorage. The regasified LNG is conveyed from the facility 735 to shorevia a pipeline 90. The solution can be advantageous for small scale LNGterminals where it may not be economical to invest in onshore LNGstorage or to install a permanently moored Floating Storage Unit (FSU).

In other variants, the offloaded gas may be used to generate power, andthe power can be transmitted to shore from the platform 730 via anelectrical power cable.

Two specially designed hoses reels with floating LNG hose are installedon the platform 730, and the platform 730 is further equipped withcomplete LNG regasification system, power generation system and otherfacilities required to enable a complete the facility.

The above example is given with use of two barges to be towed by tugs.However, in other variants, the same principle may also be used with anytype of small-scale LNG ships. An alternative is to convert old platformSupply Vessels (PSV's) to LNG ships. Currently, there are a number orPSV's in lay-up due to reduced activity in the upstream oil & gassector. Such PSV's may therefore be converted to small-scale LNG shipsthat will be attractive to use in combination with the SRP as described.A key advantage of such PSV's compared to traditional LNG ships is thatthe PSV's normally are equipped with Dynamically Position System (DP)and several thrusters and propellers to obtain unique manoeuvringcapabilities.

With such DP system, mooring of the PSV to seabed moored buoys (e.g.CBM) can take place without tugs. During heavy weather, the DP system atthe PSV may also be used to assist in positioning of the vessel inaddition to the mooring lines provided by the mooring system.

Possible Advantages and Applications

The system solutions described above for jetty-less terminals maysignificantly reduce the overall cost for construction of new LNGreceiving terminals. Furthermore, higher availability and uptime may beobtained as the FSU can be designed to stay at location on a permanentbasis. Hence, the FSU (or FSRU) does not need to be disconnected andremoved from the LNG terminal in case of strong wind or high waves. Thiscan help to achieve the highest possible gas delivery regularity for newLNG receiving facilities.

Provision of the regasification, power production, and/or waterproduction on jack-up platforms can offer flexibility, convenience ofuse, and suitability for adverse weather. The jack-up platform can bebuilt at any yard and towed location by a tug boat. When arrived atlocation, it can simply be installed using it its leg jacking system andwithout use of any large installation vessels or other expensivefacilities. This in effect makes the jack-up platforms“self-installing”. A self-installed jack-up platform providing theregasification facility can significantly lower overall cost compared totraditional solutions. After installation, the jack-up platform will besituated well above the exposed wave zone, and will therefore avoidexposure to high wave forces, such that it may be well suited for use inareas exposed to large waves and strong wind (hurricane, cyclone andmonsoon areas). The jack-up platforms may also be removed and relocatedto another LNG terminal location without use of expensive installationvessels. The jack-up solution can enable a very flexible andcost-effective installation of a regasification platform 30. No specialor expensive installation vessels are needed for providing the terminal.The jack-up solution can also enable offshore LNG terminals with aregasification facility to be installed at shallower water depth thantypically possible with the traditional spread moored FSRU. This canallow the length of the high-pressure gas pipeline to the onshorefacilities to be minimized and may increase location flexibility.

In the systems described above, an old and inexpensive LNG Carrier canbe used to provide the storage vessel 20 (constituting an FSU). Anadvantage of using the FSU together with a separate jack-upregasification platform 30 can be that expensive LNG regasificationequipment and associated facilities can be installed on a newly builtjack-up platform instead of by converting an LNG carrier to an FSRU.This may make it possible to use an old LNG carrier (e.g. 25 years old)as the FSU until it has to be scrapped (e.g. after an 5-10 additionalyears of use). Then, this retired FSU can be replaced with another oldFSU that may operate for the next 5-10 years. This can have cost andavailability benefits and can increase flexibility. The mooring systemsmay therefore be re-used (typical lifetime 25-30 years). The requiredmodification of the LNG storage vessel 20 (FSU) can be very moderate andextensive life extension of the FSU can be minimized.

The jack-up regasification platform solution can also help to solveanother challenge that traditional spread moored FSRU techniques arefacing. Since the regasification platform is fixed to the seabed, theplatform will not move in waves. Hence, a fixed, static high-pressurepipeline can be used from the deck of the regasification platform anddown to the seabed, rather than flexible gas risers which can be exposedto significant wave dynamics in extreme weather, (hurricane, cyclones,etc.), as used in prior art solutions of connecting an FSRU to aPipe-Line End Manifold (PLEM) and as often can be a limiting factor asto whether an FSRU can be installed at a given location or not. In theexamples of the invention, LNG transfer from the storage vessel (FSU) 20to the regasification platform 30 can advantageously be by use of LNGhoses arranged well above the wave action zone.

The solution of providing offshore power production on a jack-upplatform using regasified LNG, e.g. the platform 230, can beadvantageous for the same or similar reasons as described above forregasification in relation to installation, conveyance (in this case ofpower) to shore, weather, and location, etc. Installing the power planton the platform 230 offshore may avoid space/cost restrictions as mayotherwise be associated with onshore installation. The produced powercan be conveniently transmitted to shore by use of a high-voltage powercable.

Utilizing a jetty-less liquefaction platform 130 in combination with anold and inexpensive storage vessel 20 (FSU), may allow for stranded gasto be liquified and transported by vessel to consumers in a way that canbe economical to develop. Large amounts of “stranded” natural gas can befound at offshore and onshore fields around the world far away fromexisting gas pipelines such that they can be considered “stranded” inlocation. In such cases, the only economical way to transport such gasto the consumers may be to liquefy the natural gas to LNG and transportit to the consumers by LNG ships, and the liquefaction platform 130 canfacilitate such activity. The platform 130 can conveniently also be usedin a near shore configuration where the gas is fed from an onshorelocation. The solution of the liquefaction platform 130 can otherwise beadvantageous in a similar way to the regasification platform 30 inrelation to installation, fluid conveyance (in this case of gas to theplatform 130), weather, and location, etc. A particular advantage can bethe relocation flexibility as some of the “stranded” gas fields may havea moderate amount of gas. The liquefaction platform may therefore berelocated several times between various stranded gas fields during itslifetime.

Also, the solution of water generation platform on the jack-up 330 isadvantageous in a similar way to the regasification platform 30 inrelation to installation, fluid conveyance (in this case of fresh waterto shore), weather, and location, etc. The solution can facilitateprovision of fresh water for developing countries and clean gas powerfor consumers.

The use of the travel unit 60 can allow ship to ship transfer of LNG fora spread moored FSU (or FSRU) via spread-mooring lines installed fromthe deck level of the FSU 20 where the LNG carrier is moored typical 150m from the FSU. The LNG carrier can therefore be moored withoutinterference with the deck mounted FSU mooring lines, but yet beconnected readily to the LNG carrier 10 for transfer of LNG. Thesolution can cope well with high sea states and avoids problems ofrelative movement between the LNG carrier and the storage vessel 20 ascan typically occur when moored in a side-by-side configuration withtypically 5 m vessel separation. This may facilitate higher LNG transferregularity than for example side by side mooring to the FSU.

The small-scale solution using the offshore regasification platform 730served by tugs and barges can be advantageous for the same or similarreasons as described above for regasification e.g. by the jack-upplatform 30 in relation to installation, conveyance of gas (regasifiedLNG) and/or power to shore, weather, and location, etc. A number ofsmall-scale LNG receiving facilities are planned to be installed inhurricane/cyclone exposed areas like Caribbean and South-East Asia. Inthe event of extreme weather, the temporary storage vessel, e.g. thebarge or PSV, can disconnect from the connecting tubing, and leave indue time before the hurricane/cyclone arrives at the site. The onlyfacilities that is left in place is then the regasification platform 730and the mooring buoys. Since the regasification platform 730 is jack-upand elevated well above the maximum wave height, the platform can bevery well suited for such locations.

At many locations, the primary need may be electric power. Such need maybe particularly apparent for countries with island communities e.g.where there are thousands of small islands such as Indonesia,Philippines, or the Caribbean. A small offshore LNG to Power solutionmay therefore be perfectly suited for these locations. The solutions ofthe regassification platform 730 in combination with a temporary storagevessel e.g. barge or PSV, may also be expanded to include offshore powergeneration on the same platform 730 as the regas equipment is installed.In such case, no gas pipeline will be needed between the platform andshore. Instead, a high-voltage power cable may be used to transmit powerto shore with minimum of power loss.

The solution of transfer using the platform tower 530 can be usefulwhere onshore regasification may be preferred. It can nonethelessbenefit from use of an old FSU located offshore as the LNG storage.

The solution uses areal LNG hoses and the connection between the LNGhoses and the pipe in pipe (PIP) pipeline via the inside column 31 canthus be protected from any wave forces (more safe and robust solution).The tower provides an effective fixed connection on the seabed to thepipe in pipe pipeline 90 and overcomes challenges in risks of exposurein prior art submerged LNG hoses in the event of waves and extremeevents such as e.g. a 100-year wave as well as Tsunami condition.

Small scale LNG business may be facilitated by the solution of the“circular” regasification unit 630 for import of smaller quantities ofLNG (say 20,000-30,000 m³) by use of smaller LNG ships.

In areas mentioned above typically are exposed to hurricanes, cyclonesand monsoons, the solution can provide robust LNG receiving terminal.Motion characteristics of such a circular unit can be verified to bevery favorable when exposed to large waves compared to for instance abarge-shaped or ship-shaped hull. Bi-lobe tanks can have a well provenperformance in an LNG containment system.

1. A system for offloading liquefied gas from a cargo vessel andregasifying the offloaded gas at a location offshore, the systemcomprising: a floating storage unit which is moored to the seabedoffshore; first tubing for offloading liquefied gas from the cargovessel to the storage unit; a jack-up platform positioned offshore inproximity to the floating storage unit, the jack-up platform comprisinglegs which are arranged to be supported on the seabed and a hull whichis arranged to be jacked up along the legs to a position above the seasurface; a regasification facility on the jack-up platform; secondtubing extending between the storage unit and the regasificationfacility of the jack-up platform for transferring liquified gas from thecargo vessel to the regasification facility for regasification of theliquified gas; and third tubing for communicating regasified gas awayfrom the regasification facility.
 2. The system as claimed in claim 1,wherein the floating storage unit comprises a ship which isspread-moored to the seabed.
 3. The system as claimed in claim 1, whichfurther includes the cargo vessel, and the cargo vessel is spread-mooredto the seabed.
 4. The system as claimed in claim 1, wherein theliquified gas comprises liquefied natural gas, LNG, or liquefiedpetroleum gas, LPG.
 5. The system as claimed in claim 1, which furthercomprises a floating travel unit which is configured to travel betweenthe storage unit and the cargo vessel to connect an end of the firsttubing to the cargo vessel, the floating travel unit being arranged totravel into position to be positioned adjacent to the cargo vessel andcomprising a lifting and handling device, the lifting and handlingdevice being configured to reach over a side of the cargo vessel when sopositioned and further configured for maneuvering and landing the end ofthe first tubing onto a landing surface adjacent to a cargo manifold ofthe cargo vessel for connection thereto.
 6. The system as claimed inclaim 5, which further comprises a chain crawling propulsion systemcomprising at least one seabed anchored chain, the travel unit beingarranged to draw in the chain so as to be moveable across sea into theposition adjacent to the cargo vessel for connection of the firsttubing.
 7. The system as claimed in claim 1, wherein the cargo vessel ismoored side-by-side to the floating storage unit.
 8. The system asclaimed in claim 1, which does not use or require a jetty or jettymooring of at least one of the storage unit and the cargo vessel.
 9. Thesystem as claimed in claim 1, further comprising a power plant on thejack-up platform on which the regasification platform is provided oranother jack-up platform, the power plant being configured to besupplied with regasified gas from the regasification facility.
 10. Thesystem as claimed in claim 1, further comprising a power plant and afresh water generation facility being configured to be powered usingelectrical power generated by the power plant, the fresh watergeneration facility disposed on any one of: the jack-up platform onwhich the regasification facility is provided; a jack-up platform onwhich the power plant is provided; and another jack-up platform.
 11. Asystem for offloading liquefied gas from a cargo vessel at a locationoffshore, the system comprising: a floating storage unit which is mooredto the seabed; first tubing for offloading liquified gas from the cargovessel to the storage unit; a regasification facility; an intermediatestructure positioned offshore in proximity to the storage unit, theintermediate structure arranged to be supported on the seabed; aconnection manifold above the sea surface on the intermediate structure;second tubing configured to extend between the storage unit and theconnection manifold on the intermediate structure for transferringliquified gas from the cargo vessel to the intermediate structure; andthird tubing arranged on the seabed for conveying liquefied gas from theintermediate structure to the regasification facility.
 12. The system asclaimed in claim 11, wherein the regasification facility is locatedonshore.
 13. The system as claimed in claim 11, further comprising afixed length conduit for fluidly connecting the manifold with the tubingon the seabed.
 14. The system as claimed in claim 11, wherein theintermediate structure comprises a tower arranged to extend upward fromthe seabed and penetrate through the sea surface to an elevatedlocation.
 15. The system as claimed in claim 14 when dependent uponclaim 13, wherein the conduit comprises an internal conduit in thetower.
 16. The system as claimed in claim 11, further comprising aregasification facility onshore or close to shore, and the third tubingis configured for transporting the liquified gas from the intermediatestructure to shore for regasification at the regasification facility.17. The system as claimed in claim 11, wherein the floating storage unitincludes a regasification facility.
 18. The system as claimed in claim11, which further comprises a floating travel unit which is configuredto travel between the storage unit and the cargo vessel to connect anend of the first tubing to the cargo vessel, the floating travel unitbeing arranged to travel into position to be positioned adjacent to thecargo vessel and comprising a lifting and handling device, the liftingand handling device being configured to reach over a side of the cargovessel when so positioned and further configured for manoeuvring andlanding the end of the first tubing onto a landing surface adjacent to acargo manifold of the cargo vessel for connection thereto.
 19. Thesystem as claimed in claim 18, which further comprises a chain crawlingpropulsion system comprising at least one seabed anchored chain, thetravel unit being arranged to draw in the chain so as to be moveableacross sea into the position adjacent to the cargo vessel for connectionof the first tubing.
 20. A system for offloading liquefied gas from acargo vessel and regasifying the offloaded gas at a location offshore,the system comprising: a floating storage unit which is moored to theseabed offshore, the floating storage unit comprising an uprightcylindrical hull; tubing for offloading fluid from the cargo vessel tothe storage unit; and a regasification facility on the floating storageunit.
 21. The system as claimed in claim 20, further comprising tubingfor transporting the regasified gas from the regasification facility toshore.
 22. The system as claimed in claim 20, wherein the hull comprisesa plurality of Bi-lobe storage tanks disposed along a circumference ofthe hull.
 23. A system for offloading liquefied gas from a cargo vesselat a location offshore and regasifying the offloaded gas, the systemcomprising: a floating storage unit which is moored to the seabedoffshore; tubing for offloading fluid from the cargo vessel to thestorage unit; at least one jack-up platform; and a regasificationfacility; wherein any one or more of the regasification facility, apower production facility, and a water generation facility, is disposedon the jack-up platform; the power production facility being operableusing regasified gas from the regasification facility.
 24. The system asclaimed in claim 23, wherein at least one of the regasificationfacility, power production facility, and water generation facility isprovided on the jack-up platform, and at least one other of theregasification facility, power production facility and water generationfacility is provided on the floating storage unit.
 25. The system asclaimed in claim 23, wherein the regasification facility is provided onthe floating storage unit, and either or both the water regenerationfacility and the power production facility is disposed on the jack-upplatform.
 26. The system as claimed in claim 25, wherein at least one ofthe regasification facility; power production facility; and watergeneration facility is provided on a first jack-up platform; and atleast one other of the regasification facility; power productionfacility; and water generation facility is provided on a separate,second jack-up platform.
 27. The system as claimed in claim 23, whereinthe floating storage unit comprises either a ship or an uprightcylindrical hull arranged having circular or near-circular outerdiameter at the sea surface.
 28. The system as claimed in claim 23,which further comprises a power cable for transmitting electrical powerproduced from the power production facility away from the facility, e.g.to shore.
 29. A system for offloading liquefied gas from at least onecargo vessel and regasifying the offloaded gas at a location offshore,the system comprising: a jack-up platform; tubing for offloadingliquified gas from the cargo vessel to the jack-up platform; and aregasification facility on the jack-up platform for regasifying theoffloaded gas.
 30. The system as claimed in claim 29, further comprisingtubing for conveying gas from the regasification facility to shore orother receiver or user.
 31. The system as claimed in claim 30, whereinthe tubing comprises a fixed length conduit, e.g. in rigid or innon-flex configuration, e.g. extending vertically, for conveying gasaway from the regasification facility to a pipeline on the seabed. 32.The system as claimed in claim 29, which further comprises a powerproduction facility operable to produce power using gas from theregasification facility.
 33. The system as claimed in claim 32, whichfurther comprises power cable for transmitting electrical power to shoreor other receiver or user.
 34. The system as claimed in claim 33,wherein the power cable comprises a fixed length cable, e.g. in rigid orin non-flex configuration, between the power facility and a subsea cableon the seabed for transmission to shore or other receiver or user. 35.The system as claimed in claim 32, wherein the power production facilityis provided on the jack-up platform or another jack-up platform.
 36. Amethod of offloading liquified gas from at least one cargo vessel andregasifying the offloaded gas at a location offshore, the methodcomprising providing a cargo vessel carrying liquefied gas; providing ajack-up platform and a regasification facility on the jack-up platform;utilizing tubing to offload the liquefied gas from the cargo vessel tothe jack-up portion; regasifying the gas with the regasificationfacility; and operating a power production facility to produce powerusing the gas from the regasification facility.
 37. A system forliquefying gas and loading the liquefied gas onto a cargo vessel and ata location offshore, the system comprising: a floating storage unitwhich is moored to the seabed; a jack-up platform positioned offshore inproximity to the floating storage unit, the jack-up platform comprisinglegs which are arranged to be supported on the seabed and a hull whichis arranged to be jacked up along the legs to a position above the seasurface; a liquefaction facility on the jack-up platform; first tubingfor loading liquefied gas fluid from the floating storage unit to thecargo vessel; second tubing extending between the floating storage unitand the liquefaction facility of the jack-up platform for transferringliquified gas from the liquefaction facility to the cargo vessel; andthird tubing for transporting the gas to the liquefaction facility. 38.The system as claimed in claim 37, which further comprises a floatingtravel unit which is configured to travel between the storage unit andthe cargo vessel to connect an end of the first tubing to the cargovessel, the floating travel unit being arranged to travel into positionto be positioned adjacent to the cargo vessel and comprising a liftingand handling device, the lifting and handling device being configured toreach over a side of the cargo vessel when so positioned and furtherconfigured for maneuvering and landing the end of the first tubing ontoa landing surface adjacent to a cargo manifold of the cargo vessel forconnection thereto.
 39. The system as claimed in claim 38, which furthercomprises a chain crawling propulsion system comprising at least oneseabed anchored chain, the travel unit being arranged to draw in thechain so as to be moveable across sea into the position adjacent to thecargo vessel for connection of the first tubing.
 40. A method ofliquefying gas and loading liquified gas onto a cargo vessel, the methodcomprising: mooring a floating storage unit to a seabed in proximity toa jack-up platform positioned offshore, the jack-up platform comprisinglegs which are arranged to be supported on the seabed and a hull whichis arranged to be jacked up along the legs to a position above the seasurface; providing a liquefaction facility on the jack-up platform; andproviding first tubing for loading liquefied gas fluid from the floatingstorage unit to the cargo vessel, second tubing extending between thefloating storage unit and the liquefaction facility of the jack-upplatform for transferring liquefied gas from the liquefaction facilityto the cargo vessel, and third tubing for transporting the gas to theliquefaction facility.